The ongoing focus of the laboratory is to understand in detail the structure/function relationships of cell surface molecules involved in the immune response. In particular we have made significant progress over the past year in five areas: A. Using molecular engineering techniques to generate genes capable of encoding soluble murine class I major histocompatibility complex (MHC) antigens; B. Using the purified soluble antigens derived from these cells to analyze the biochemical and functional behavior of soluble H-2Dd; C. Analyzing the origin and function of proteins derived from alternatively spliced mRNAs of the class I antigens H-2Dd and H-2Kb; D. Analyzing the structure-function relationship of class I molecules by a detailed serological, biochemical and functional study of H-2Dd/H-2Ld chimeric proteins; E. Studying the function of in vitro class II/class I chimeric genes.